dingsdax

# extension for array class
class Array
   # select array items with index
   # give a block both the item with index of array
   # filtered by a select statement
   def select_with_index
     index = -1
     select { |x| index += 1; yield(x, index) }
   end
   # return indices array of array item

dingsdax

# extension for string class
class String
  # return character array of string with indices
  def each_char_with_index
    i = 0
    split(//).each do |c|
      yield i, c
      i += 1
    end
  end